1. Field of the Invention
The present invention relates to a sealing tape and a method and apparatus for its production, and a method of repairs with it, and more particularly to a sealing tape for covering, in a car body, an exposed metal surface, a joint between metal plates, a shoulder portion in joint, and like stepped portions.
2. Description of the Prior Art
In the manufacture of automobiles, it has been the practice to apply a sealing agent to joint portions and joint shoulder portions in car bodies such as body panel joints and hemming portions in door and hoods of the car bodies to prevent water and dust from entering the car bodies. More specifically, as shown in FIG. 15, in case that an inner metal plate B is inserted into and jointed to a bent portion C of an outer metal plate "A" which is provided with the bent portion C in its end portion, a joint shoulder portion D extending in a direction perpendicular to the plane of the drawing paper is covered with a strip of sealing agent E having been squeezed out of a tube through its nozzle, so that the thus sealed joint shoulder portion D extends in the direction perpendicular to the drawing paper.
The application of this sealing agent E to the car body is carried out by an industrial robot during the manufacture of the car or automobile. Consequently, it is possible to control, with high accuracy, both the amount of the sealing agent E being squeezed out through the nozzle and a traveling distance of the nozzle, which enables the sealing agent E having been applied to the car body to assume a constant shape in cross section, as shown in FIG. 14. The application of the sealing agent E to the car body is followed by the application of paint.
When the joint of car body panels is deformed by an impact applied to the car, it is necessary to repair such deformed joint so as to have the joint return to its original shape in appearance.
In such repairing and paint application of the car body, after completing the repair in shape of the joint of the car body panels, the sealing agent E is applied to the joint in a manner such that: the nozzle of the tube, which is made of, for example, metal and filled with the sealing agent E, is manually brought into direct contact with a joint of the car body by an auto worker; and, the sealing agent E is also manually squeezed out of the tube through the nozzle thereof while the nozzle of the tube is manually moved along the course of the joint by the worker, whereby the application of the sealing agent E to the course of the joint is manually carried out by the worker.
In such manual operations, it is very difficult for the worker to keep constant the amount of the sealing agent E applied to the course of the joint even when he concentrates his attention on his work in which he must constantly squeeze the sealing agent E out of the tube as he moves the tube along the course of the joint. In other words, in most cases, the worker fails to accurately trace the course of the joint, which results in an uneven finishing surface of the sealing agent E thus applied to the joint. Due to this failure, the joint of the body panels thus repaired fails to assume the same shape as that of a joint of body panels in a new car. The shape of the joint in a new car is shown in FIG. 15 in cross section.
Previous to the present invention, the inventor of the subject application has already proposed a conventional sealing tape 10. This sealing tape 10 enables a user to seal the joint of car body panels with it in a very easy manner, and the joint thus sealed with the tape 10 is excellent in finishing.
As shown in FIG. 14, the conventional sealing tape 10 assumes an relatively thick strip-like shape with a stepped bottom surface, and is made of vulcanized rubber material to resiliently keep its original shape. In use, such conventional sealing tape 10 is adhesively applied to a joint shoulder portion of metal plates (See, Japanese Utility Model Registration No. 3,004,875).
For example, as shown in FIG. 13, in application of the conventional sealing tape 10 assuming the above shape to the joint shoulder portion D located between the outer or first metal plate "A" and the inner or second metal plate B which is inserted into and jointed to the bent portion C of the first metal plate "A" which is provided with the bent portion C in its end portion, the sealing tape 10 has its first bottom surface portion 11, which is opposite to a curved portion 14 of the tape 10, and its second bottom surface portion 12, which is opposite to a flange edge portion 15 of the tape 10, adhesively applied to the metal plates "A" and B, respectively.
As a result, both the first bottom surface portion 11 and the second bottom surface portion 12 of the conventional sealing tape 10 may firmly adhere to the joint shoulder portion D located between the metal plates "A" and B, which ensures that the joint shoulder portion D is sufficiently sealed up.
However, for example, as shown in FIG. 12, when the conventional sealing tape 10 is used in a joint shoulder portion of metal plates of an inner side of a car rear door (an upholstery lining panel of which is removed in FIG. 12), it is necessary to bend the sealing tape 10 at substantially right angles in a manner such that the sealing tape 10 extends along a corner portion G of the door to adhere to the corner portion G.
In this case, the sealing tape 10 often slacks in or separate from the corner portion G of the door, which impairs the door in its surface finish quality. In order to improve the door in such surface finish quality, it is necessary to manually apply the sealing agent E to this corner portion G of the door as is in the conventional application.
The above-mentioned slacking and separation of the sealing tape 10 occurs because of its resiliency. In other words, since the sealing tape 10 is made of rubber material having been vulcanized and assumes a strip-like or elongated shape with resiliency, such slacking and separation occurs in the corner portion G of the door. In general, rubber material is vulcanized to assume a fixed shape of a desired rubber product, because rubber material not vulcanized may vary in shape under pressure. Consequently, such rubber material not vulcanized is not adequate for the purpose of the sealing tape which must keep its shape for a long period of time in use.